Developing and integrating tactics to slow ash (Oleaceae) mortality caused by emerald ash borer (Coleoptera: Buprestidae)

Abstract Practical and effective strategies to manage emerald ash borer (EAB) (Agrilus planipennisFairmaire; Coleoptera: Buprestidae) are increasingly important given economic and ecological impacts of this invader. While EAB detection remains challenging, tactics are available to protect individual ash (FraxinusLinnaeus; Oleaceae) trees and slow EAB population growth, thereby delaying ash mortality. Simulations with a coupled map lattice model, parameterised with data from numerous field studies, showed treating trees with a highly effective systemic insecticide (TREE-äge™; emamectin benzoate), would be more effective in slowing EAB population growth than girdling trees to attract ovipositing females then destroying trees before larvae develop, while harvesting ash to reduce available phloem would have the least effect. From 2008 to 2012, cooperators participated in a pilot project to implement an integrated strategy for an EAB infestation in Upper Michigan, United States of America. Ash was inventoried and EAB density monitored using girdled ash detection trees supplemented with baited artificial traps across the >750 km2project area. While only a tiny fraction of ash trees in the project area were girdled (444–855 trees annually) or injected with TREE-äge™ (<360 roadside trees annually), and treatment distribution was restricted, both treatments slowed EAB population growth. Coupling TREE-äge™ injections with other tactics will likely yield additive or synergistic outcomes.